1. Field of the Invention
The present invention relates to a dichroic mirror, to a fluorescence filter set, and to a fluoroscopy apparatus, such as a microscope or endoscope for fluoroscopy, a measurement device for measuring fluorescence intensity, and so forth.
This application is based on Japanese Patent Application No. 2004-214620, the content of which is incorporated herein by reference.
2. Description of Related Art
Known dichroic mirrors according to the related art include those disclosed below, for example.
A dichroic mirror described in Japanese Unexamined Patent Application Publication No. HEI-11-202127 includes a multilayer film formed, on a transparent substrate, by alternately laminating high-refractive-index layers, intermediate-refractive-index layers, and low-refractive-index layers having optical film thicknesses equal to ¼ of a design center wavelength λ0.
A dichroic mirror described in Japanese Unexamined Patent Application Publication No. SHO-61-45202 includes alternating layers formed, on a substrate, by alternately laminating high-refractive-index layers having an optical film thickness equal to ¼ of a reference wavelength λ0, and low-refractive-index layers having an optical film thickness equal to ¾ of the reference wavelength λ0.
A dichroic mirror described in Japanese Unexamined Patent Application Publication No. SHO-54-110855 (Japanese Examined Patent Application Publication No. SHO-62-27361) includes alternating layers formed by alternately laminating, on a substrate, high-refractive-index layers having optical film thicknesses equal to ¼ and ¾ of a reference wavelength λ0, and low-refractive-index layers having optical film thicknesses equal to ¼ and ¾ of the reference wavelength λ0.